Cartridge-type soldering iron with inert gas emitted near the tip

ABSTRACT

A soldering iron heats the tip and emits inert gas near the tip. This is accomplished by providing a heater cartridge having a top or tip end and a base end with a soldering tip at the top end, an input opening closer to the base end and an output opening closer to the top end. The soldering iron also includes a gas injector having a gas chamber adapted to receive the heater cartridge such that the input opening of the heater cartridge is within the gas chamber so that gas is injected into the input opening. At least a portion of the top end and the output opening of the heater cartridge is enclosed with an exhaust pipe to form a gas passage between the outer surface of the heater cartridge and the exhaust pipe. As such, gas injected through the input opening passes through the opening within the heater cartridge and exits through the output opening, then passes through the gas passage and emits through an outlet defined by the space between the top end and the exhaust pipe to provide inert gas near the tip.

BACKGROUND OF THE INVENTION

1. Related Applications

This application claims priority to two Japanese patent applications, (1) 2003-101427, filed Apr. 4, 2003; and (2) 2003-118048, which was filed Apr. 23, 2003, which are both hereby incorporated by reference.

2. Field of the Invention

This invention relates to a cartridge-type soldering iron capable of performing soldering operations and emitting inert gas, and more particularly, to a cartridge-type soldering iron capable of soldering operations in a constricted space.

3. General Background and State of the Art

As printed circuit boards are discarded, lead (Pb) embedded in the circuit board can release into the environment. The release of lead into the environment can lead to environmental hazards. To remedy this problem, some have developed soldering compounds that are free of lead. One of the drawbacks with lead free solder, however, is that the melting point of lead-free solder is 30° C. to 50° C. higher than the melting level of 210° C. to 232° C. of lead solder. This means that a soldering tip temperature of 350° C. or higher must be maintained in order to perform soldering operations with lead free solder. With such a high soldering tip temperature, flux in the solder can deteriorate, which can cause rapid oxidation in the soldering tip. As such, when lead free solder is used, the life of the soldering tip is shortened.

Various solutions to the above problems have been proposed, including the methods described in Japanese Utility Model Application Laid-Open No. H6-70962 and U.S. Pat. No. 6,247,631. The preferred method described in No. H6-70962 relates to a cartridge-type soldering iron where threaded solder is supplied automatically. This is accomplished by providing a soldering iron having a heating element with a bent top end, and a handle that intersects with the body of the heater and forcing the thread solder into the bent top end of the heating element. As such, the soldering iron disclosed in the '962 application cannot be applied to a cartridge-type soldering iron where the soldering tip and the handle are arranged in a straight line. In addition, to form a flow path for the inert gas, a cylindrical pipe attached to the heating element projects at an angle from the handle. This cylindrical pipe obstructs precise soldering operations, and it is difficult to precisely position the cylindrical pipe in order to maintain a uniform flow path for the inert gas. The supplied thread solder also hinders the soldering operation, so that it is generally not used in a printed circuit board with a high degree of concentration.

The '631 patent attempts to solve the shortcomings of the '962 application with a cartridge-type soldering iron where the soldering tip and the handle are arranged in a linear configuration. Projections are provided on an outer periphery of the heating element and the inner periphery of the pipe, and the heating element and the pipe are precisely positioned to provide a uniform flow path for the inert gas. However, the plurality of projections on the outer periphery of the heating element and the inner periphery of the pipe in the '631 patent are inherently inefficient. Accordingly, a more easily produced cartridge-type soldering iron is desirable. A cartridge-type Pb-free soldering iron with readily interchangeable soldering tips that can be replaced by the user without special tools is also highly desirable.

INVENTION SUMMARY

This invention provides a soldering iron that heats the tip and emits inert gas near the tip. This is accomplished by providing a heater cartridge having a top or tip end and a base end with a soldering tip at the top end, an input opening closer to the base end and an output opening closer to the top end. The soldering iron also includes a gas injector having a gas chamber adapted to receive the heater cartridge such that the input opening of the heater cartridge is within the gas chamber so that gas is injected into the input opening. At least a portion of the top end and the output opening of the heater cartridge is enclosed with an exhaust pipe to form a gas passage between the outer surface of the heater cartridge and the exhaust pipe. As such, gas injected through the input opening passes through the opening within the heater cartridge and exit through the output opening, then passes through the gas passage and is emitted through an outlet defined by the space between the top end and the exhaust pipe to provide inert gas near the tip.

The soldering iron described above works efficiently and conveniently even at high temperatures, while preventing oxidation of the soldering tip. Further, according to the invention, in its assembled state, a uniform gas flow path can be formed around the heating element of the cartridge-type soldering iron without creating obstacles to the use of the soldering iron in constricted spaces. The invention also makes possible a much more compact cartridge-type soldering iron, further aiding in the performance of precise soldering operations, and can perform soldering operations while emitting inert gas.

Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within the description, be within the scope of the invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.

FIG. 1 is a perspective view showing the cartridge-type soldering iron in a disassembled state.

FIG. 2 is a perspective view showing the disassembled elements of a cartridge-type soldering iron according to an embodiment.

FIG. 3 is a cross-sectional view of the front end of the cartridge-type soldering iron shown in FIG. 1.

FIG. 4( a) is a cross-sectional view of a gas injecting device of FIG. 2.

FIG. 4( b) is a front view of the gas injecting device of FIG. 4( a).

FIG. 4( c) is a rear view of the gas injecting device of FIG. 4( a).

FIGS. 5( a) through 5(C) are side view of a handle portion of the soldering iron.

FIG. 6( a) is a perspective view of the conductive part embedded in the handle portion.

FIG. 6( b) is a front view of the conductive part shown in FIG. 6( a).

FIG. 6( c) is a cross-sectional view taken along a line C—C in FIG. 6( a).

FIG. 7( a) is a cross-sectional view of the conductive part shown in FIG. 6( a) taken along a line A—A.

FIG. 7( b) is a cross-sectional view along the line B—B of the conductive part in FIG. 6( a).

FIG. 7( c) is a close up view of the base end of the heater cartridge.

FIG. 7( d) is a close up view of the terminal plate.

FIG. 7( e) is a close up view of the base end of the terminal body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a cartridge-type soldering iron (soldering iron) 1 including an exchange member 100 and a connector member 102 adapted to receive the exchange member 100. FIG. 2 is a perspective view illustrating the disassembled elements of the soldering iron 1. The exchange member 100 includes a heater cartridge 2, a gas-exhaust pipe 3 capable of coupling to a top or tip end of the heater cartridge 2, and a grip handle 4 configured to receive the heater cartridge 2. The grip handle 4 couples to the heater cartridge 2 along a central portion of the heater cartridge 2. The connector member 102 includes a handle base 5 with an inner configuration adapted to receive the base end of the heater cartridge 2 and the outer surface configured so that the top end of the handle base 5 is enclosed within a gas injector 6. The connector member 102 further includes the gas injector 6 coupled to the handle base 5 for injecting inert gas into the heater cartridge 2, and an electric connector 8 positioned on a terminal end of cable 7 that extends from the handle base 5.

An inert gas supply tube (not shown) is coupled to the gas injector 6. As such, when the soldering operation is to be changed, the operation can be carried out continuously only by exchanging the exchanging member 100. The gas exhaust pipe 3 is coupled to the heater cartridge 2 from the front, and a grip handle 4 is coupled to the heater cartridge 2 from the behind. As a result, the gas exhaust pipe 3, the heater cartridge 2, and the grip handle 4 are assembled as an integral unit.

When the assembly comprising the gas exhaust pipe 3, the heater cartridge 2, and the grip handle 4 is inserted into the handle base 5, the cartridge-type soldering iron 1 is fully assembled. In this case, the base end of the grip handle 4 is abut against the top end of the gas injector 6, thereby preventing the excessive insertion of the heater cartridge 2. In this configuration, minimal stress if any may be applied to the base end of the heater cartridge 2. The gas exhaust pipe 3, the heater cartridge 2, and the grip handle 4 is integrally formed and this formation may be prepared as an exchange member 100. Alternatively, the heater cartridge 2 to which the gas exhaust pipe 3 is coupled may be prepared as the exchange member 100.

Once the connection member 102 is assembled, the base end of the grip handle 4 is in contact with the gas injector 6, and the contact point between the grip handle 4 and the gas injector 6 is closer to the top end than the center point of the entire length of the cartridge-type soldering iron 1. The diameter of the grip handle 4 is the proper size to be gripped comfortably by three fingers (thumb, index and middle finger) and the grip handle 4 is manufactured of material of appropriate elasticity. Therefore, intricate soldering operations may be performed on highly integrated printed circuit boards.

As shown in FIGS. 2 and 3, the heater cartridge 2 includes a cylindrical, conductive hollow pipe 9, a soldering tip 10 coupled to the top or tip end of the hollow pipe 9, a mounting part 11 coupled to an outer periphery of the hollow pipe 9, and a heater part 12 inserted into a mounting hole 10 a of the soldering tip 10. The heater part 12 is provided with a temperature sensor 13 at its top end. The heater part 12 and the temperature sensor 13 are held in position by a ceramic coat material 14 filled in the mounting hole 10 a. The ceramic coat material 14 may be solidified water solution including binder and alumina, or any other insulatory material known to one skilled in the art.

FIG. 3 illustrates that two conductors 15 a and 15 b extend from the heater part 12 passing through the hollow pipe 9. The two conductors 15 a and 15 b are electrically connected to annular terminals 16 a and 16 b on the base end side of the hollow pipe 9. The base end of the heater cartridge 2 is substantially closed with an insulation material 17 a (as shown in FIG. 2). The base end of the heater cartridge 2 is hermetically sealed in the handle base 5 when the soldering iron 1 is in use, so that inert gas injected into the hollow pipe 9 does not leak from the handle base 5. As explained below, the base end side of the handle base 5 is substantially closed, and the top end side thereof is hermetically sealed by the hollow pipe 9 and the elastic body 27 b.

In the base end of the hollow pipe 9, insulation materials 17 b and 17 c are respectively disposed between the annular terminal 16 a and the annular terminal 16 b, and between the annular terminal 16 b and the pipe body 16 c, such that the three members 16 a, 16 b and 16 c are electrically insulated from one another. The pipe body 16 c of the hollow pipe 2 is electrically connected to the soldering tip 10.

FIGS. 2 and 3 illustrate that the pipe body 16 c is formed with a plurality of (e.g., four) first holes 18 located near the top side of the mounting part 11, and is formed with a plurality of (e.g., two) second holes 19 at locations corresponding to the gas injector 6. Inert gas is injected into the hollow pipe 2 through second holes 19, and discharged through first holes 18. The second holes 19 are separated from each other along the same circumference of the pipe body 16 c. The first holes 18 are separated away from one another in an axial direction and in a circumferential direction of the pipe body 16 c. Two projections 50 and 51 are provided between the rear end and the mounting part 11 of the pipe body 16 c. The outer peripheral diameters of the projections 50 and 51 are substantially the same as an inner peripheral diameter of the grip handle 4 so that the outer periphery of the projection 50 is substantially fit within an inner periphery of the grip handle 4. As a result, deflection between the grip handle 4 and the heater cartridge 2 along the radial direction is substantially prevented.

The projection 51 engages with a step (not shown) formed in the inner periphery of the grip handle 4 when the grip handle 4 is inserted from the rear end of the heater cartridge 2 so that the projection 51 positions the grip handle 4 in a predetermined position along the axial direction. That is, before the top end of the grip handle 4 comes into contact with the mounting part 11, the projection 51 prevents the grip handle 4 from being further inserted.

FIG. 3 illustrates that the gas exhaust pipe 3 includes a plurality of portions: an inner portion 20; an outer portion 21; and a box nut 22. The inner portion or pipe 20 is slightly larger in diameter than the hollow pipe 9. The outer portion or pipe 21 is tightly fitted around the outside of the top end of the inner pipe 20. The cylindrical box nut 22 is movably fitted into an outer periphery of the inner pipe 20. The top end of the outer pipe 21 is tapered to conform to the shape of the soldering tip 10. The inner pipe 20 is formed at its base end with a flange part 20 a which has a large diameter formed into an annular shape diametrically outward. To accommodate a plurality of differently shaped soldering tips designed to accomplish various different soldering operations, a plurality of differently shaped outer pipe 21 to fit different soldering tip 10 may be provided.

As shown in FIG. 3, the box nut 22 is divided into the top end 22 a and the base end 22 b, which have different inner peripheral diameters. An inner peripheral surface of the base end 22 b is formed with a threaded groove corresponding to the mounting part 11. The inner peripheral diameter of the top end 22 a is greater than an outer diameter of the inner pipe 20; The inner peripheral diameter of the top end 22 a is smaller than the outer diameter of the flange part 20 a of the inner pipe 20 and the outer diameter of a base end of the outer pipe 21. As such, the box nut 22 is not detached from the inner pipe 20 either in its forward or backward direction.

The inner peripheral diameter of the base end 22 b of the box nut 22 is substantially the same as the outer peripheral diameter (r) of the flange part 20 a. Contact surfaces between the top end 22 a of the box nut 22 and the mounting part 11 which abut against the front and rear surfaces of the flange part 20 a intersect with an axial direction of the hollow pipe 9 at right angles in correspondence with the flange part 20 a. As such, if the box nut 22 is screwed onto the mounting part 11 and the flange part 20 a is pushed against the contact surface of the mounting part 11, the inner pipe 20 is positioned correctly with respect to the box nut 22 as shown in FIG. 3. Once the box nut 22 is screwed, the box nut 22, the mounting part 11 and the inner pipe 20 are integrally coupled so that the inner pipe 20 is positioned correctly with respect to the hollow pipe 9, thereby forming a uniform gap between the inner pipe 20 and the hollow pipe 9, to provide a gas passage.

With the soldering iron described above, unlike U.S. Pat. No. 6,247,631, it is unnecessary to provide a positioning projection on the inner peripheral surface of the inner pipe 20 or the outer peripheral surface of the hollow pipe 9, to provide a uniform gas passage. FIG. 3 illustrates that inert gas introduced from the first holes 18 passes through the gas passage formed between the hollow pipe 9 and the inner pipe 20 toward the top end, reaches a gas passage formed between the outer pipe 21 and the soldering tip 10, and is emitted toward an operation surface. Since the inert gas is emitted as described above, the oxidation of the soldering tip is minimized. The base end of the gas passage is closed by tight contact between the flange part 20 a and the mounting part 11.

As shown in FIG. 2, the grip handle 4 is comprised of a plastic inner cylindrical body 23 and an elastic polymer outer cylindrical body 24 enclosing the plastic inner cylindrical body 23. In this embodiment, PVC (polyvinyl chloride) is used as the elastic polymer, but other elastomers, including rubber, may be used. The inner cylindrical body 23 and outer cylindrical body 24 are made of material having low thermal conductivity so that the outer cylindrical body 24 can be comfortably grasped by the user. Different colors of elastic polymer of the outer cylindrical body 24 may be used to distinguish a plurality of different outer cylindrical bodies.

The inner cylindrical body 23 is provided with a flange part 23 a which receives the insertion of the outer cylindrical body 24. The rear end of inner cylindrical body 23 is axially notched by a plurality (in one embodiment, four) of notched grooves 23 b in the axial direction. The elastic body rings 25 a and 25 b are fitted around the notched grooves 23 b. The elastic body rings 25 a and 25 b reduce the diameter of the end of the inner cylindrical body 23, which are then inserted into outer cylindrical body 24. In this manner, cylindrical body 23, and cylindrical body 24 are combined to form the grip handle 4. When inner cylindrical body 23 is inserted into outer cylindrical body 24 they are integrally coupled, then this assembly may receive the hollow pipe 9. Outer cylindrical body 24 has an appropriate elasticity, and its outer diameter is of a size to be comfortably grasped by three fingers (the thumb, index and middle fingers).

While the diameter of hollow pipe 9 may be small in accordance with degree of integration of IC mounted on a printed circuit board, the diameter of outer cylindrical body 24 is adapted to fingers of an operator. Further, the contact point between outer cylindrical body 24 and the gas injector 6 is slightly closer to the tip than the central point of the soldering iron 1. As a result, the soldering iron 1 is more comfortable to use in soldering operations.

FIG. 4 illustrates that the gas injector 6 includes a sealing screw 30. The top end and base end of the charging body 26 are hermetically sealed by O-rings 27 a and 27 b. O-ring 27 a is held by a pushing plate 28(FIG. 2), and the O-ring 27 b is held in place by the top end surface of handle base 5. The base end of charging body 26 is cylindrical in order to receive handle base 5, and the handle base 5 is fixed in place by holding screws 31. The charging body 26 has a mounting opening 33 into which an introducing member 32 is inserted. Inert gas introduced through the introducing member 32 moves inward and then reaches a central gas chamber 34.

The inert gas used with the soldering iron 1 may be nitrogen gas. The inert gas is supplied through a tube (not shown) coupled to the introducing member 32. The tube is disposed along the axial direction of the soldering iron to not obstruct with soldering operations. The supply of inert gas through the tube member mounted to introducing member 32 is controlled by an ON/OFF toggle switch (not shown).

The diameter of gas chamber 34 is slightly greater than that of hollow pipe 9. When hollow pipe 9 is inserted into gas chamber 34, the ends of gas chamber 34 are sealed by O-rings 27 a and 27 b. When hollow pipe 9 is inserted into handle base 5, the second holes 19 of hollow pipe 9 are located at the gas chamber 34. As such, the inert gas in gas chamber 34 passes through the second holes 19 into hollow pipe 9. With the top end and the base end of hollow pipe 9 being sealed as discussed above, the inert gas is discharged from the holes 18.

FIGS. 5( a) through 5(c) illustrate a cylindrical first part 35 opened at both axial ends, and a cap-shaped second part 36 is screwed onto the linkage part 43, providing a handle base 5. The first part 35 includes an electrical connector assembly 37. When the top end 35 a is inserted into the base end of the body 26 of a gas injector part 6, the top end 35 a makes contact with elastic body 27 b. Therefore, when the heater cartridge 2 is inserted into the handle base 5, a secure seal is formed by the outer periphery of the hollow pipe 9 and the elastic body 27 b.

FIG. 5( a) illustrates that the handle base 5 is separated into first part 35 and second part 36. The base end of second part 36 is closed by cable 7 inserted into this base end and leads 44, 45, 46 are derived from cable 7 as shown in FIG. 5( b). In order to close the base end of second part 36 securely, a sealing member may be adhered to the outer periphery of the cable 7 and forcibly inserted into the base end of second part 36.

The linkage part 43 includes a body 43 a having screw grooves in axial opposite ends and attachment plates 43 b, 43 c projecting frontward and rearward in an axial direction from the body 43 a. The body 43 a has three penetration holes passing three leads 44, 45 and 46. The attachment plate 43 c couples to the top end of the cable 7 from the second part 36, and the attachment plate 43 b couples the linkage part 43 with the electrical connector assembly 37.

FIG. 6( a) illustrates that the electrical connector assembly 37 is formed with a ground terminal plate 40, a first terminal plate 41, and a second terminal plate 42 built into a plastic terminal body 39 of the electrical connector assembly 37. Although not shown, the ground terminal plate 40, the first terminal plate 41, and the second terminal plate 42, are respectively connected with the leads 44, 45, 46 derived from the cable 7 and passing through body 43 a.

FIG. 7( e) illustrates that the terminal body 39 is cylindrical, and an installation hole 46 corresponding to the terminal plate 40, an installation hole 47 corresponding to the terminal plate 41, and an installation hole 48 corresponding to the terminal plate 42 are formed in the base end side of the terminal body 39. Each installation hole 46, 47 and 48 is respectively divided into installation groove 46 a, 47 a and 48 a, with a breadth of L1, and installation openings 46 b, 47 b and 48 b, with a breadth of L2. The first terminal plate 41 is inserted from the installation hole 47 at the base end of terminal body 39 toward the top end, and the second terminal plate 42 is inserted from the installation holes 48 toward the top end. The first and second terminal plates 41 and 42 are thus fixed to the terminal body 39.

FIG. 7( a) illustrates that the first rectangular windows 51 a and 51 b and the second rectangular windows 52 a and 52 b are formed in the terminal body 39 in a radially symmetric direction. The third rectangular window 53 b is 90 degrees apart from windows 51 b and 52 b as shown in FIG. 7( b). The first rectangular windows 51 a and 51 b correspond to the first terminal plate 41, the second rectangular windows 52 a and 52 b correspond to second terminal plate 42, and the third rectangular window 53 b corresponds to ground terminal plate 40.

As shown in FIGS. 7( a) and 7(c), the inner diameter φ′ of terminal body 39 is the same as or slightly greater than the outer diameter φ of hollow pipe 9. The axial length of terminal body 39 is sufficient to contain two annular terminals 16 a, 16 b and the base end of handle body 16 c.

The ground terminal plate 40 shown in FIG. 7( b) extends to the top end side of the terminal body 39 and couples with the annular electrical conductor 38. In FIG. 6( a), the annular electrical conductor 38 is made of an elastic material and a notch 38 a is formed throughout an axial direction in a part of its circumference. Therefore, annular electrical conductor 38 becomes radially telescopic. When contracted, the annular electrical conductor 38 is inserted into terminal body 39, and spreading more or less in a radial direction, the annular electrical conductor 38 is securely inserted into the terminal body 39.

As shown in FIG. 7( a), in the axial center of the annular electrical conductor 38, a small diameter projection 38 b projects inward radially around the entire circumference. The inner diameter of small diameter projection 38 b is slightly smaller than the outer diameter φ of hollow pipe 9. Therefore, when heater cartridge 2 is inserted into handle base 5, the small diameter projection 38 b extends slightly in an axial direction or outward in a radial direction by the hollow pipe 9. Thus, small diameter projection 38 b contacts and holds the hollow pipe 9 securely.

FIGS. 7( a) and 7(c) illustrate that the projection 38 b is formed in a position of contact with the pipe body 16 c. As such, the electrically secure ground terminal 40 is connected with the pipe body 16 c through the small diameter projection 38 b when the heater cartridge 2 is inserted into handle base 5. Further, the ground terminal 40 is inserted from the top end of the terminal body 39 (see the left side of FIG. 7) into the base end and a projecting cut piece 40 b of ground terminal plate 40 is engaged with the third small window 53 b of the terminal body 39. Thus, the insertion is completed as shown in FIG. 7( b).

The first terminal plate 41 is smaller than the second terminal plate 42, and both plates are made of an elastic material. In FIG. 7( d), the first and second terminal plates 41 and 42 comprise bodies, top ends and base ends. The width of terminal plates 41 and 42 is almost the same as the width L1 of installation holes 47 a, 48 a. The width of the top ends of terminal plates 41 and 42 is slightly smaller than the width L2 of installation openings 47 b and 48 b. The base ends of the terminal plates 41 and 42 provide stoppers ST to prevent excessive insertion. As shown in FIG. 7( d), projecting cut piece 41 b is formed in the body of first terminal plate 41, and the stopper ST and an opening 41 c connected with the lead 45 are formed in the base end of first terminal plate 41. Likewise, the projecting cut piece 42 b is formed in the body of the second terminal plate 42 and the stopper ST and an opening 42 c are formed in the base end of second terminal plate 42, as shown in FIG. 7( a).

When the first terminal plate 41 and the second terminal plate 42 are inserted into the installation holes 47 and 48, the plates 41 and 42 slide into installation grooves 47 a and 48 a respectively, and the stoppers ST come into contact with terminal body 39. In this state of contact, projecting cut pieces 41 b and 42 b are engaged with rectangular windows 51 b and 52 b of terminal body 39, respectively, to securely hold terminal plates 41 and 42.

FIG. 7( a) illustrates that the tops of terminal plates 41 and 42 are bent radially inward. In a free state, the bent parts 41 a, 42 a are located inside the outer diameter of the hollow pipe 9. In FIG. 7( c), with hollow pipe 9 inserted, bent part 41 a of the first terminal plate 41 makes contact with annular terminal 16 a and bent part 42 a of the second terminal plate 42 makes contact with the annular terminal 16 b.

The first terminal plate 41 makes an electrically secure connection with annular terminal 16 a and the second terminal plate 42 makes an electrically secure connection with annular terminal 16 b. In this manner, when terminal plates 41 and 42 are supported, bent parts 41 a and 42 a of the top end only swing and terminal plates 41 and 42 of this embodiment receive no pressure from the hollow pipe 9. Therefore, the stress due to the insertion of the hollow pipe is substantially minimized.

The electrical connection is made by bringing the two terminal plates 41, 42 of different lengths into contact with the two annular terminals 16 a, 16 b respectively. No rotational orientation is necessary when the heater cartridge 2 is inserted. With this invention, the complexity of inserting the heater cartridge 2 into the electrical connector assembly 37 may be minimized. Moreover, in a state in which the hollow pipe 9 is inserted, the ground terminal 40 is securely connected making an electrical contact with the pipe body 16 c as explained above.

The outer diameter of the hollow pipe 9 is almost the same as the inner diameter of terminal body 39, such that the hollow pipe 9 is held loosely within terminal body 39. On the other hand, the pipe body 16 c spaced properly from the base of the pipe is held securely over its entire length by annular electrical conductor 38. As such, when hollow pipe 9 is inserted into the electrical connector assembly 37, the hollow pipe 9 is held securely by electrical connector assembly 37. That is, with the length of the terminal plate 41 being different from that of the terminal plate 42, the distance from the base end of the electrical connector assembly 37 to small diameter projection 38 b inevitably becomes long, so that hollow pipe 9 can be more securely held.

As shown in FIG. 1 the grip handle 4 and handle base 5 are separated. When hollow pipe 9 is inserted into the grip handle 4, heater cartridge 2, gas exhaust pipe 3, and the grip handle 4 are combined as a single unit. As such, the soldering iron 1 is used for a variety of operations by replacing the exchange member 100 comprised of heater cartridge 2, gas exhaust pipe 3 and grip handle 4. That is, when a soldering tip 10 is to be changed, the assembly comprising a heater cartridge 2, gas exhaust pipe 3 and grip handle 4 may be pulled out integrally. And an exchange member 100 comprising another soldering tip 10, may be inserted into gas injector 26 and handle base 5. In addition, to expedite the selection of an appropriate soldering tip, the cylindrical body 24 of grip handle 4 of each exchange member 100 may be made of a different color material.

In addition to the exchange member 100 described above, another exchange member may be constructed with the gas exhaust pipe 3 and the heater cartridge 2, both integrally coupled. Such exchange member, the heater cartridge 2 of the exchange member is inserted into grip handle 4 which has been used heretofore and grip handle 4 is used as it is.

The grip handle 4 is detachably fitted over the heater cartridge 2, so that it is possible to produce a grip handle having the shape, size, color and material desired by a user. Further, since each user may have a personal grip handle, sanitation level is high, and when the grip handle becomes worn it may be replaced without having to replace the entire cartridge-type soldering iron, thereby reducing costs.

It is understood by those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope thereof. For example, although the cartridge-type soldering iron in which the grip handle 4 and the handle base 5 can be separated from each other, the present invention can also be applied to a cartridge-type soldering iron in which the grip handle 4 and the handle base 5 are integrally coupled with each other, and then the heater cartridge 2 is inserted into the integral grip handle 4 and handle base 5.

While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of this invention. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. 

1. A system for soldering and emitting inert gas, comprising: a soldering tip; a heater cartridge made of a conductive pipe, and including the soldering tip at its top end, and annular terminals at a base end thereof, the terminals being electrically connected to a heater part within the heater cartridge; a gas injector adapted to provide gas through an input opening of the heater cartridge; an exhaust pipe adapted to enclose at least a portion of the heater cartridge to provide a gas passage; and a handle base adapted to receive the base end of the heater cartridge and including a grounding terminal, a first terminal, and a second terminal, where the grounding terminal extends toward the top end and is electrically connected to the conductive pipe, a part of the grounding terminal is pushed and widened by the inserted heater cartridge.
 2. The system according to claim 1, further including a mounting part coupled to the heating cartridge between an input opening and an output opening, where the mounting part is adapted to couple to the exhaust pipe.
 3. The system according to claim 2, further including a box nut, where the exhaust pipe includes an inner pipe with a flange adapted to receive the heater cartridge, and the box nut is movably fitted over an outer periphery of the inner pipe and coupled with the mounting part to couple the inner pipe with the mounting part.
 4. The system according to claim 1, where the soldering tip is adapted to receive the heating part at least partially within the soldering tip.
 5. The system according to claim 1, further including a box nut and the exhaust pipe has a base end formed with a flange part oriented diametrically outward, where the box nut engages with the flange part to couple the exhaust pipe to the mounting part.
 6. The system according to claim 1, where the exhaust pipe includes an outer pipe and the soldering tip projects through the outer pipe forming an outlet between the soldering tip and the outer pipe.
 7. The system according to claim 1, where the gas injector has a gas chamber adapted to receive the heater cartridge so that the input opening is within the gas chamber, where the gas injector further has a mounting opening that provides a passage between a gas introducing member and the gas chamber so that gas can be provided through the input opening of the heater cartridge; and where the gas chamber is between sealing members so that gas can only pass through the input opening of the heater cartridge.
 8. The system according to claim 1, further including a temperature sensor disposed within the soldering tip to measure the temperature of the soldering tip.
 9. The system according to claim 1, where the gas injector is mounted to the handle base.
 10. The system according to claim 1, where a part of the grounding terminal in its circumferential direction is notched.
 11. The system according to claim 1, where the first terminal and the second terminal are embedded in a nonconductive part disposed in the handle base.
 12. The system according to claim 11, where the first terminal and the second terminal are plate materials whose top ends are bent diametrically inward, where one of the plate materials is shorter than the other plate material.
 13. The system according to claim 1, where the first terminal and the second terminal are plates whose top ends are bent diametrically inward, and where one of the plates is shorter than the other plate. 